[$] Recent disruptive changes from Setuptools

In late March, version 78.0.1 of Setuptools — an important
Python packaging tool — was released. It was scarcely half an hour before
the first bug
report came in, and it quickly became clear that the change was far
more disruptive than anticipated. Within only about five hours 78.0.2 was
published to roll back the change, and multiple discussions were
started about how to limit the damage caused by future breaking
changes. Nevertheless, many users still felt the response was
inadequate. Some previous Setuptools releases have also caused problems on a smaller but still notable scale, and hopefully the developers will be more cautious going forward. But there are also lessons here for the developers of Python package installers, ordinary Python developers and end users, and even Linux distribution maintainers.